Young men who have sex with men (YMSM) remain a critical population in need of empirically supported approaches to improve self-management to promote reduced HIV sexual risk behaviors and substance use. The Young Men?s Health Project (YMHP), a structured and manualized 4-session intervention utilizing motivational interviewing, personalized feedback, and problem-solving skills building approaches for HIV-negative or untested youth was found to be efficacious in significantly reducing substance use and condomless anal sex (CAS) among YMSM ages 18-29. To date, this is the first and only RCT of any published trial or CDC DEBI with YMSM to show significant reductions in both substance use and sexual risk. The CDC recently rated YMHP as ?Best Evidence? and placed it on the compendium of Evidence Based Interventions and Best Practices for HIV Prevention. YMHP was tested through an efficacy trial in a research center environment with numerous inclusion and exclusion criteria, and thus, a real-world-based replication is the crucial next step in studying the intervention?s effectiveness in the real world when delivered by front-line staff to their clients. We will conduct a comparative effectiveness trial (CET) with two modalities of YMHP delivery ? clinic-based and telephone-based ? at three HIV clinic sites in Los Angeles, Philadelphia, and Miami. The Specific Aims are to: 1) adapt the YMHP intervention for clinic and phone delivery in HIV clinics by community health workers (CHWs); 2) compare the effectiveness of clinic-based versus phone-based delivery of YMHP in the context of health care access, assessing the cost effectiveness of both modalities and the five components of the selfmanagement model; and 3) test a sustainable model of YMHP implementation in real-world adolescent HIV clinics. The proposed study will be implemented over two phases. In Phase 1 we will conduct qualitative research with staff at our collaborating clinics (to understand implementation issues) and YMSM ages 15-17 (to adapt the efficacious YMHP intervention to be developmentally appropriate). In Phase 2 we will randomize 270 YMSM ages 15-24, to receive YMHP by phone or in person at the clinic. Assessments will include behavioral self-report measures, urine testing for substance use, and STI testing for sexual health outcomes. Working together with our clinic collaborators will help to address practical problems at the frontline of service provision to pave the way for a comprehensive program to reduce HIV infection among YMSM. If effective, our program has the potential to exert a sustained and powerful influence on the effectiveness of behavioral interventions for YMSM.